Filmstrip advancing mechanism

ABSTRACT

A filmstrip advancing mechanism has a sprocket turned on a shaft carrying a sleeve with a clutch between the sleeve and the shaft. A knob turns the shaft and is movable axially to disengage the clutch for turning the shaft relative to the sleeve. The sleeve is detentable to stop the shaft at successive frame positions of the filmstrip. The sleeve carries a ratchet having a number of teeth equal to the number of detent stops, and a pivotally reciprocal pawl is mounted on the projector to engage and advance the ratchet teeth for advancing the filmstrip. A solenoid depresses the pawl lever on a signal from a tape deck accompanying the projector, and a manual button is also arranged for actuating the pawl.

0 s, United States atet [151 3,680,754 McFadden et al. 451 Aug, 1, 1972[54] FILMS 4? P ADVANCHNG MECHANISM 3,003,393 10/1961 Kilday ..352/ 163X [72] Inventors: gr m? figi gif 53 2222 Primary Examiner-Allen N.Knowles both of Attorney-Cumpston, Shaw & Stephens [73] Assignee:Graflex, Inc., Rochester, NY. [57] ABSTRACT [22] Filed: Sept. 30, 1970 Afilmstrip advancing mechanism has a sprocket turned on a shaft carryinga sleeve with a clutch [21] Appl 76764 between the sleeve and the shaft.A knob turns the shaft and is movable axially to disengage the clutchfor [52] US. Cl; ..226/76, 226/127, 352/163 turning the she-ft relativeto e eeve. The sleeve is 51 Int. Cl... ..G03b 1/42 detehtable to Stopthe Shaft at Successive frame P [53] Field of Search 2 5 7 7; 3 52 tionsof the filmstrip. The sleeve carries a ratchet having a number of teethequal to the number of detent [56] References Cited stops, and apivotally reciprocal pawl is mounted on the projector to engage andadvance the ratchet teeth UNITED STATES PATENTS for advancing thefilmstrip. A solenoid depresses the pawl lever on a signal from a tapedeck accompanying 1,738,762 12/1929 De Vault ..352/163 X the projector,and a manual button is also arranged for 2,037,454 4/1936 Boeckmg..352/163 actuating the pawL 2,534,731 12/1950 Perillo ..352/163 X2,458,346 1/1949 Charlin ..352/163 X 4 Claims, 7 Drawing FiguresPATENTEDAUG 1 I972 WHHIHIHHHIHminimum sum 1 or a c INVENTE 2R5 PATENTEUH972 3,680,754

sum 2 OF 3 ROBERT N. McFADDEN FRANK L. BLAAKMAN INVENTORS ATTORNEYSPATENTEDAus H972 3,680,754

' sum 3 BF 3 H WW II I HI' U FIG. 5

5 I ROBERT N. McFADDEN I: 6 FRANK 1.. BLAAKMAN I I3 INVENTORS WNW BYW WATTORNEYS FILMSTRIP ADVANCING MECHANISM THE INVENTIVE IMPROVEMENTvancing mechanism allows both automatic and manual 4 operation in simpleand convenient ways, and it provides for quick and easy framing of thefilmstrip.

SUMMARY OF THE INVENTION The inventive filmstrip advancing mechanismuses a rotatable shaft with a sprocket for advancing the filmstrip andcarrying a sleeve that is rotatable and axially movable on the shaft.The shaft and sleeve each carry a clutch part, and a spring biases theclutch parts together so the shaft normally turns with the sleeve. Aknob for turning the shaft is axially movable to compress the spring todisengage the clutch for turning the shaft relative to the sleeve. Thesleeve has circumferentially evenly spaced detentable regions, and aresilient detent engages these regions for stopping the sleeve atsuccessive frame positions of the filmstrip. A ratchet on the sleeve hasa number of teeth. The pawl is actuated either by a solenoid underautomatic control or by a manual push-button.

DRAWINGS FIG. 1 is a partially schematic, front-elevational view of apreferred embodiment of a filmstrip projector using the inventive filmadvancing mechanism;

FIG. 2 is a partially schematic, cross-sectional view of the projectorof FIG. 1 taken along the line 2 2 thereof;

FIGS. 3 5 are partially sectioned, fragmentary views of a preferredembodiment of filmstrip advancing mechanism in the projector of FIG. 1;and

FIG. 6 is a partially schematic view of an alternative embodiment of aportion of the inventive filmstrip advancing mechanism.

DETAILED DESCRIPTION Projector 10, as schematically illustrated, is arear screen filmstrip projector for projecting an image from filmstrip12 onto rear screen 11, (FIGS. '1 and 2). A sprocket 13 advancesfilmstrip 12 through film gate 14, and light from a source 15 isdirected through condenser lenses 16, filmstrip l2, lens system 17, andmirror 18 which reflects a projected image onto rear screen 11. Sprocket13 turns the proper amount to advance filmstrip 12 one frame at a timeand such film advance is either manual through a push-button 39 (FIG. 3)or automatic under control of tape deck 20 which includes a synchronizer19 for advancing filmstrip 12in synchronization with a tape played intape deck 20. A signal recorded on the tape is used by synchronizer 19to actuate the inventive film advancing mechanism for such automaticadvance.

The details of a preferred embodiment of the inventive film advancingmechanism are best shown in FIGS. 3 5. A shaft 21 carries sprocket l3,and shaft 21 is turned a step at a time to advance filmstrip 12 oneframe for each step. A sleeve 22 carried on shaft 21 is both rotatableand axially movable relative to shaft 21, and sleeve 22 is used foradvancing and detenting shaft 21 as explained more fully below.

A knob 23 is secured to shaft 21 and extends over sleeve 22. A clutchpart 24 on sleeve 22 faces a confronting clutch part 25 on the base ofknob 23 to provide a clutch engagement between sleeve 22 and shaft 21through knob 23. Clutch part 24 is fixed on sleeve 22, and knob 23 andshaft 21 are movable axially relative to sleeve 22. A compression coilspring 26 abuts against clutch part 24 and flange 27 of knob 23 which isfixed to shaft 21. Spring 26 thus urges knob 23 and shaft 21 to the leftas illustrated in FIG. 4, to keep clutch parts 24 and 25 normallyengaged so that shaft 21 turns with sleeve 22.

If knob 23 is pushed to the right as illustrated in FIG. 4 to compressspring 26, clutch parts 24 and 25 are disengaged so that shaft 21 can beturned independently of sleeve 22 for accurate framing of filmstrip 12.Sleeve 22 is held still in a detented position while shaft 21 is turnedfor framing, and release of knob 23 after framing re-engages clutchparts 24 and 25 to set sleeve 22 and shaft 21 in the proper angularrelationship for advancing filmstrip 12 accurately, frame-by-frame.

A detent region 28 of sleeve 22 is made square, and a resilient armdetent 29 engages detent region 28 to stop sleeve 22 at successiverotational positions. Sprocket 13 is sized relative to filmstrip 12 toadvance filmstrip 12 one frame for each 90 rotation so that after properframing, detent arm 29 cooperates with detent region 28 to positionsuccessive frames of filmstrip 12 for accurately framed projection.

A ratchet 30 on sleeve 22 has four teeth 31 cor responding to the foursides of detent region 28, and a pawl 32 carried on pawl lever 33 isarranged for engaging and advancing the teeth 31 of ratchet 30. Pawl 32is vertically pivotal so it can be depressed, as best shown in FIGS. 3and 3a, to drive ratchet 30 clockwise, as illustrated, in a 90 turn fordetented film advance. Pawl lever 33 is carried on pivot pin 34 for thispurpose, and a slot 35 in pawl lever 33 allows some longitudinal motionof lever 33 on pin 34 as well as pivotal motion. A spring 36 fixed toprojector 10 biases pawl lever 33 upward for return motion after eachactuation.

Automatic advance of filmstrip 12 is accomplished by solenoid 37 coupledto pawl lever 33 by connecting arm 38 so that energization of solenoid37 pulls down arm 38 to depress lever 33 and force pawl 32 against atooth 31 for a 90 advance of ratchet 30. Solenoid 37 is preferablyenergized on a signal from synchronizer 19 in response to tape deck 20to advance filmstrip 12 one frame on each signal from a tape.

Manual advance is accomplished by push-button 39 carried on lever arm 30which is pivoted on pin 34 and biased upward by spring 41. Lever arm 40has a projection 42 that overlies pawl lever arm 33 so that when arm 30is depressed by button 39, projection 42 forces pawl lever arm downwardto actuate ratchet 30. When pawl arm 33 is actuated by solenoid 37,button 39 and arm 40 remain upward under the bias of spring 41.

FIG. 6 shows an alternative arrangement for detenting and advancingsleeve 46 on shaft 21 carrying sprocket 13. A clutch part 43 is securedto shaft 21 by collar 44, and one face of a four-tooth ratchet 45 onsleeve 46 engages clutch part 43 for a clutching action. A square detentregion 47 is arranged adjacent ratchet 45, and a spring 48 between knob49 and sleeve 46 provides the axial bias for normal engagement of clutchpart 43 with ratchet 45. Pushing knob 49 inward disengages clutch part43 to allow framing as described above, and the operation of a pawl withratchet 45 and a detent against detent region 47 is the same aspreviously described.

Persons wishing to practice the invention should remember that otherembodiments and variations can be adapted to particular circumstances.Even though one point of view is necessarily chosen in describing anddefining the invention, this should not inhibit broader or relatedembodiments going beyond the semantic orientation of this applicationbut falling within the spirit of the invention. For example, thoseskilled in the art will understand that many variations and alternativescan be used to fit the circumstances of particular front and rear screenprojectors.

We claim:

1. An improved filmstrip advancing mechanism for a filmstrip projector,said advancing mechanism comprising:

a. a rotatable shaft;

b. a sprocket turned with said shaft to advance said filmstrip;

c. a sleeve on said shaft;

d. said sleeve being rotatable and axially movable relative to saidshaft;

e. a first clutch part on said shaft;

f. a second clutch part on said sleeve;

g. a spring arranged for biasing said first and second clutch partstogether so said shaft normally turns with said sleeve; v

h. a manually turnable knob on said shaft for turning said shaft;

i. said knob being arranged to move axially to compress said spring todisengage said clutch for turning said shaft relative to said sleeve;

j. said sleeve having circumferentially evenly spaced detentableregions;

k. a resilient detent disposed to engage said regions for stopping saidsleeve at successive frame positions of said filmstrip;

l. a ratchet arranged on said sleeve;

m. said ratchet having a number of teeth equal to the number of saiddetentable regions; 4

n. a pawl pivotally mounted on said projector to engage and advance saidratchet teeth;

o. pawl including a vertically reciprocal lever; and

p. means on said projector for actuating said pawl.

2. The filmstrip advancing mechanism of claim 1 wherein said pawlactuating-means includes a solenoid arranged for depressing said pawllever.

3. The filmstrip advancing mechanism of claim 1 including a manuallydepressable button, and means for depressing said pawl lever when saidbutton is depressed.

4. The filmstrip advancing mechanism of claim 3, wherein said pawlactuating means includes a solenoid arranged for depressing said pay/llever.

1. An improved filmstrip advancing mechanism for a filmstrip projector,said advancing mechanism comprising: a. a rotatable shaft; b. a sprocketturned with said shaft to advance said filmstrip; c. a sleeve on saidshaft; d. said sleeve being rotatable and axially movable relative tosaid shaft; e. a first clutch part on said shaft; f. a second clutchpart on said sleeve; g. a spring arranged for biasing said first andsecond clutch parts together so said shaft normally turns with saidsleeve; h. a manually turnable knob on said shaft for turning saidshaft; i. said knob being arranged to move axially to compress saidspring to disengage said clutch for turning said shaft relative to saidsleeve; j. said sleeve having circumferentially evenly spaced detentableregions; k. a resilient detent disposed to engage said regions forstopping said sleeve at successive frame positions of said filmstrip; l.a ratchet arranged on said sleeve; m. said ratchet having a number ofteeth equal to the number of said detentable regions; n. a pawlpivotally mounted on said projector to engage and advance said ratchetteeth; o. pawl including a vertically reciprocal lever; and p. means onsaid projector for actuating said pawl.
 2. The filmstrip advancingmechanism of claim 1 wherein said pawl actuating means includes asolenoid arranged for depressing said pawl lever.
 3. The filmstripadvancing mechanism of claim 1 including a manually depressable button,and means for depressing said pawl lever when said button is depressed.4. The filmstrip advancing mechanism of claim 3, wherein said pawlactuating means includes a solenoid arranged for depressing said pawllever.